After a hypodermic syringe has been used by a physician or nurse to give an injection to a patient, it is recommended that this syringe be altered to prevent reuse. The Cowley U.S. Pat. No. 3,320,954 describes one system of altering the syringe. This includes breaking the needle adapter at a circumferential score line.
In the past such a scored needle adapter system for altering the syringe was not suitable for syringes having a Luer lock sleeve. The rigid Luer lock sleeve surrounding the needle adapter prevented bending the needle adapter to its breaking point. The relationship between the Luer lock sleeve and the needle adapter is shown in the Cowley U.S. Pat. No. 3,301,256. In this Cowley patent a rigid band on a segmented Luer lock sleeve prevented any significant outward flexure of the Luer lock sleeve.